Glass containers are typically formed by an IS machine, that is, a machine with multiple side by side sections, such as six or eight or even ten sections, and in modern practice multiple containers, such as three or four containers, are often simultaneously formed at each section by a process commonly referred to as the multiple gob process. In any case, a gob distributor is required to sequentially distribute gobs of molten glass to each section of an IS machine, and a multiplicity of such gob distributors are required for a multiple gob IS machine, one gob distributor for each of the sets of molds (blank mold/container mold) of an IS machine section.
Each gob distributor of the type described above has a curved scoop and requires a drive unit to index an oscillating member to which the scoop is attached. The oscillating member is driven in a series of incremental steps as the scoop sequentially aligns itself with a series of gob chutes, one leading to one of the blank molds at each of the sections of the IS machine. During the pause of the gob distributor scoop at each IS machine section chute, a gob of molten glass from an outlet orifice of the feeder bowl of a glass melting furnace forehearth, after severing of a stream of molten glass therefrom into a gob of predetermined weight, passes through the scoop of the distributor and then through the chute into a blank mold of the IS machine section. The scoop of the gob distributor must be at rest as the gob passes therethrough, to avoid slinging of the gob due to centrifugal force, and it must be very precisely aligned with the blank mold chute as the gob passes from the scoop into the chute.
A typical drive unit for an IS forming machine gob distributor incorporates a power source with a vertical output shaft and a driven member to which the gob scoop oscillating member is attached. The driven member has a vertical input shaft, which is spaced from the output shaft of the power source. Heretofore, torque was transmitted from the output shaft of the power source to the input shaft of the driven member through a gear train. However, a gear train inherently has a relatively high amount of backlash associated with it, which interferes with the precise positioning of the gob scoop with respect to the blank mold chutes it is to be sequentially aligned with. This problem is compounded in modern IS machine installations where the gob distributor may be required to cycle as often as 25 times per minute, whereas typical older installations required cycle rates of no more than 15 to 17 times per minute. Further, higher cycle rates introduce maintenance and lubrication problems into a gob distributor system, which increase the complexity, and therefore the expense, of such a system, and the frequency of required maintenance shutdowns.
Bearings of prior art gob distributors must be continuously lubricated. Heretofore such lubrication was accomplished by a viscous grease that was sealed within the gob distributor. Occasionally, however, such grease lubrication systems were subject to undesirable moisture condensation therein and/or the incapability of the grease reaching remote regions of the gob distributor for proper lubrication of the components located in such region.
Known prior art IS machine gob distributor systems are disclosed in U.S. Pat. No. 5,135,559 (Sasso et al.), in U.S. Pat. No. 4,529,431 (Mumford) and in U.S. Pat. No. Re. 28,759 (Bystrianyk et al.), the disclosure of each of which is incorporated by reference herein.